This invention relates to a polishing apparatus for polishing and/or cleaning a planar surface by means of a polishing (or abrasive) tape adapted not only to travel longitudinally but also to undergo a rotary motion in a plane parallel to the surface to be polished. More particularly, this invention relates to such a polishing apparatus capable of polishing and/or cleaning not only flat surfaces such as surfaces of glass plates for liquid crystal devices and printed circuit boards but also surfaces of elastic curved plates such as window panes of an airplane.
Liquid crystal devices are currently being used extensively in a variety of fields of application. Liquid crystal display devices, in particular, are commonly used in many word processors, personal computers and televisions. Such a liquid crystal device is produced by carrying out various processes on glass plates such as cutting, injecting liquid crystal and attaching a polarization plate. During the course of such a production process, glass powder is usually generated copiously as glass plates are cut and liquid crystal is injected and sealed, and residual resin materials used for the sealing appear as a contaminant. It is well known that such a contaminant is a major cause of the occurrence of defective products. Prior art methods of removing such contaminants have been manual, however, using a cutting knife or a solvent such as acetone or alcohol. Manual methods of removing contaminants affect the production efficiency adversely, and it is difficult to maintain a uniform level of product quality.
In electronic devices such as word processors and personal computers, it is common to use a printed circuit board with wires formed thereon for attaching elements such as semiconductor chips. Production of such a printed circuit board includes both chemical processes such as the formation and removal of thin films and physical processes such as punching holes and cutting in order to form connecting wires. For this purpose, it is necessary to polish both the front surface and the back surface of a base plate. Prior art methods of polishing, however, included using an endless belt, etching, sand blasting and buffing, but the use of a polishing tape is becoming popular because tapes are not only capable of accomplishing desired polishing but also easy to handle.
Another problem to be solved by the present invention relates to the polishing of a plate with a curved surface. Front windows of an airplane, for example, are curved for the purpose of their use, and their surfaces are usually polished to remove scratches and/or cleaned manually by means of a hand-polisher. Manual polishing and/or cleaning operations are inefficient, and their results are not uniform, depending upon the operator who handles the polisher.